The invention relates to a support panel structure comprising at least one panel which extends in longitudinal and cross direction of the support panel structure and essentially forms one integrated structure, which integrated structure is at least partly build up of at least one composite resin laminate building block comprising at least a first and a second face sheet of a fibrous reinforced material with sandwiched in between a sheet of a foamed core material, wherein the first and second face sheet and the sheet of core material are mutually connected by means of fibrous reinforcing material at least part of which extends in height direction of the resin laminate building block, according to the preamble of the first claim.
Nowadays, practically all over the world, trucking has become one of the most important modes of transportation for goods. The inherent design of a towed trailer is long in length and narrow in width, with a high center of gravity when loaded. The trailer is usually connected to a towing truck by means of a kingpin and fifth wheel system or a kingpin and gooseneck hitch mechanism. In a gooseneck hitch mechanism, a downwardly pointing kingpin is rigidly mounted to the front of the long, curved tongue portion on the trailer, which generally has the shape of a gooseneck. The kingpin is adapted to fit into the hitch plate of the truck to which the trailer is being hitched.
The main bearing members for loads placed on vehicles, such as for instance flatbed or semi-trailers, are the pair of I-beams, generally known as the “main beams” or main runners which are made of steel and run longitudinally of the vehicle. In order to be able to offer support for loads, such as for instance containers, usually steel floor supports in the form of a multiplicity of cross members are mounted to the bottom side of the undercarriage. These cross members are bolted or welded perpendicularly to the webs of the main runners and define the width of the bed. On top of the structure formed by the longitudinal and cross members, a floor is provided, of which the floor sections are typically welded to each other along their longitudinal sides or butted against each other and held in position by special guiding means and floor screws.
WO-A-9947406 discloses a flatbed trailer that unitizes the floor, the longitudinal runners and the cross runners, to provide a lightweight, though strong trailer. However, there are several problems associated with this type of known trailer. Extensive welding of the cross members and floor sections to the main runner which extends over the whole length of the loading floor, not only reduces the load bearing strength of the complete floor structure and the loading height capacity but also adds considerable weight, and therefore requires a substantial sacrifice in load capacity. Even when materials such as for instance low density aluminum are used to increase load capacity, this attempt is defeated by the extensive welding, which is time consuming and costly, and tends to minimize payload. Moreover, since the floor is build up of essentially loose floor sections, they contribute very little to the load bearing function.
There is a general trend in the transport industry to decrease the empty chassis weight as much as possible. As the European legal limit of the total weight of a truck is 40 ton, reducing the weight of the trailer would permit increasing the load capacity.
EP-A-967.139 discloses a semi-trailer with a wheeled chassis which is lightweight to provide optimum load carrying capacity. The chassis comprises a pair of spaced-apart longitudinal runners, which extend over the entire length of the trailer. At the front portion, the chassis runners are bow shaped and they extend around the ends of a forward transverse runner. The runners taper inwardly towards the rear chassis portion, to finally run parallel, three wheel axle assemblies being mounted between them in the rear chassis portion. The runners also taper inwardly towards the front portion, so that the rubbing plate assembly can be directly mounted to the runners without the need for additional reinforcement, thus saving weight. The semi-trailer disclosed in EP-A-967.139 is suitable for use with a goose-neck as well as flat construction at its front end. However, it is made of metal and does not comprise a trailer floor.